I've never heard of middle schoolers having a gpa, but high schools have gpas to rank the students in the class, and when applying to college almost all applications have a spot for gpa. It is kind of silly though because there are so many different scales in different high schools, your gpa ends up not being very important. For example, the top gpa in my high school graduating class was around 4.7, and that kid was one of the smartest kids i have ever met, he got a perfect score on the SATs, twice, and he owns his own computer business. But, ive met kids from high schools with differnet scaled gpas who have like 5.3, its kind of ridiculous a lot of the time